Mix & Match?

I have some convicts, firemouths, and green terrors that all have breed at
the same time. Right now all fry are free swimming and I wish to keep a few
before they become fish food. If i were to mix all the cichlids together in
a grow out tank would they be ok. I have never heard otherwise but I'd
rather be safe then sorry.

My second question is at what size will I be able to put them in a tank with
2"- 4" cichlids so they are not consider food or so they do not get beat up
on. I really want to see them grow up but I don't wanna loose them from
carelessnes. If anyone has any suggestions or answers please let me know.
Thank you.